Dental chair



I(N0 Modem 6 sheets-sheen 1.

M. G. MERKER.

n vDENIM. (1H-AIR. No'. 579,094.

Patented 'Max'. 16, 1897.

/ @f4 mi QW,

'9. fd@ f -(No Model.) 5 Sheets-Sheet 3.

, M. C. IVIERKEILl DENTAL CHAIR.

No. 579,094.. Patented'MaJr. 16, 1897.

IGI

ShQets--Sheet 4.

Patented' Mar. 16.1897'.

ifi y (No Model.)

M.G;MERKBR. DENTAL YGIULIE. No. 5 79,094.

.f m MW w m M v fY 7 @u v @f f 1% mww, 1Mw mwwf, .IMA 4 w Mw v, M a

6 sheets-sheet( 5.

(No Model.)

M. G. MERKBR.

DENTAL CHAIR. y

Patented Mar. 16, 1897.

@Hom/wij fdd,

me Nonms virils co.. vnouruo., wAsumoYom-u L il'ivirn MONT C. MERKER, OFPHILADELPHIA, PENNSYLVANIA.

DENTAL CHAiR.

SPECIFICATION forming part of Letters Patent No. 579,094, dated March16, 1897. Application iiled October 26, 1896. Serial No. 610,140. (Nomodel.)

To @ZZ whom it may concern.-

Beit known that I, MONT C. MERKER, aresident of Philadelphia, in thecounty of Philadelphia and State of Pennsylvania, have inven ted certainnew and useful Improvements in' Dental Chairs; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art `to which itpertains to make and use the same.

The invention relates to dental chairs provided with seat raising andlowering mechanism, and has for its object to render the operation ofcertain parts more easy, certain, and efficient; and the inventionconsists in the construction hereinafter described and particularlypointed out.

In the accompanying drawings, Figure 1 is a vertical section of the baseof a chair and of seat raising and lowering tubes. Fig. 2 is a sectionon line 2 2 of Fig. 1. Fig. 3 isasection of Fig. 1 on line 3 3. Fig. 4is apartial vertical section on line 4 4 of Fig. 3. Fig. 5 is a sectionon line 5 5 of Fig. 4. Fig. Gis an enlarged section of a device forforcing a receptacle of the balls of a bearing outwardly. Figs. 7 and Sare enlarged sections of devices for controlling and regulating theescape of oil of the hydrostatic column that supports the seat. Fig. 9is an isometric View of a receptacle for ball-bearin gs. Fig. 10 is aside elevation of a headrest. Fig. 11 is a vertical central section ofthe same on line 11 11. Fig.

2 is a rear elevation. Fig. 13 contains isometric views of padsupporting and clamping rings. Fig. 14 is a plan of a washer. Fig. 15 isa section on line 15 15 of Fig. 11.

Numeral 1 indicates the base of a chair, 2 a rotatable pedestal, and 3 alever for locking .or clamping said base and pedestal together.

4 denotes an oil-reservoir `lixed to and rotatable with the pedestal.

5 is a casting secured in the bottom of the reservoir and directlysupporting the main part of the seat-elevating devices.

6 denotes a part of the seat-frame or seat, which may be of any usual ordesired construction. To this frame are connected seatsupporting orplunger tubes '7 and 8, the former being preferably fixed to thecross-bar and the latter bearing loosely against its under side, asshown.

9 denotes a tube fitted to slide in the upper part of the pedestal andprovided with a pro jecrion 10, adapted to engage a stop 11, fixed tothe pedestal and thus limit the ascent of said tube 9.

12 is a similar projection on tube 7, and 13 is its stop fixed to theinside of tube 9.

14 is a tube fixed in casting 5.

15 is an extension or telescoping tube situated between tubes 14 and S.Tubes 15 and 8 lare each provided at its foot with a packing and theformer with a flexible diaphragm 16, which serves as the packing for thejoint between the tube to which it is att-ached and its inclosing tubeand also acts as a piston.

17 denotes an oil-inlet tube fixed in the casting 5.

The tube 9 is a sliding extension of tube 7, fixed tothe seat-frame, andtube 15 a similar extension of tube 14, mediately fixed in the base. Thegeneral purpose and operation of similar tubes in dental chairs are wellknown. The several tubes are concentric and preferably situatedcentrally with respect to the base and pedestal, though such situationis not essential. l

The movable tubes are raised or lowered to raise or lower the chair-seatby means of a suitable liquid, preferably oil, through the medium ofdevices next to be described.

1S and 19 denote pum ps provided with valves 1S' and 19', respectively,to admit oil from the reservoir to the pump-cylinders, and also withoutlet-valves 18" and 19.

2O is a pump-operating lever (shown in dotted lines in Figs. 3 and 4)having a fulcrum at 21. It is loosely connected to the foot of aT-shaped lever 22. 20 denotes a slot in the lever and 20anantifriction-roller su 3 )or-ted bys aid Tshaped lever. Said lever isadapted to oscillate about a stud 23, iixed to the pedestal.

18' and 19 denote pistonlrods pivo'ted to the head or cross-bar of thelever 22 and to the pistons of the respective pumps. The construction issuch that when one piston is forced down the other is raised, bothoperations being effected by the lever 20. The

lever and pistons are returned to normal positions by the aid of aspring 24.

24 is a spring held between a ring or flange 25, fixed on thepiston-rod19, and a bracket IOD 2G, fixed to the pedestal. This springis compressed by the ascent of the rod caused by lever 20, and beingthus put under tension it subsequently acts to force down its piston andsimultaneously lifts rod 18" and its piston.

24 is a screw working in the bracket 2G to vary the tension of thespring. By these means one of the pumps opens the valve 19 and forcesoil through a passage 27 and under the piston 16, with the effect toraise tube l5. The other pump forces oil through passage 28 into thesmall central tube 17 and thence into the tube 8, which is therebyraised with the effect to elevate the chair-seat. The tube 17 providesthat liquid may be delivered in tube 8 above the diaphragm 16, at thefoot of tube 15, whatever be the elevation of the latter. The liquidforced into the tubes from each pump does not mingle with that from theother until it is returned to the reservoir. By the combination of thetwo pumps, their operating-levers, and the spring the lifting of theseat is made even and continuous and is more quickly eifected.

Since spring 24 not only forces down the piston of the pump with whichit is connected, but lifts the other piston and also returns the leverto its normal position, it needs to be much stronger than an ordinaryreturningspring, which would be entirely inoperative for the purpose. Toreduce as far as practicable this requirement of a spring of exceptionalpower, the pump to which it pertains is connected with the space belowthe largest tube to be elevated, which is tube 15 in thepresentinstance, whereby it is provided that pump 19 does less work thanpump 18 and the spring is so far relieved.

29 indicates balls arranged continuously in suitable endless channels30. These are in the present instance situated in adjustable boxes orreceptacles 3l, placed in or connected to the wall of the pedestal,being so arranged that the balls 'in one part of each endless groove orchannel bear on the exterior of the vertically-movable extension-tube 9.There are preferably three pairs of these ball-bearings in the pedestal,as indicated in the drawings, each box containing a pair and twoparallel channels therefor. These channels and each series of ballscontained therein are made endless to avoid the binding of the balls intheir seats or against each other. The individual series of each pairare separated by a rib 32 to prevent lateral interference.

One or more of the boxes 3l can be adjusted to hold the balls more orless closely against tube 9 by means of screws 33. It is not neeessarythat more than one be thus adjusted directly, since the adjustment ofone necessarily affects the other in equal and substantially the samemanner.

34 denotes similar antifriction devices situated in the wall of the tube7, the exterior balls bearing on the interior of extensiontube 9.

35 (see Fig. (i) indicates a wedge operated by a screw-rod 36,having ahandle 37, whereby the ball-receptacle can be crowded outwardly to causethe balls to suitably bear on the tube 9. The receptacle or thecontiguous tube has a similarly-inclined face coperating with theincline of the rod. As indicated in Fig. 3,- there are three pairs ofthese lastdescribed ball-bearin gs. The particular number is notessential; neither is the vertical arrangement of the series ofballsessential, though preferred. Obviously they might be obliquelyarranged.

The pedestal is rotatable, and with it is rot-ated the entire chairexcept the base, as is usual. To prevent the separate rotation of thetubes, a rolling-key (one or more) 38, (sce Fig. 2,) supported by asuitable axis in the pedestal, is arranged to move in a groove 39 in theexterior of tube 9, and a similarkeywheel, one or more, is journaled inthe wall of tube 7, and adapted to run in a groove formed in theinterior of said tube 9. (See Fig. 3.)

Oil is allowed to escape through branches 27' and 2S' from the tubes tolower the chairseat by opening the cock 40, which simultaneously opensor closes said branches. (See Figs. 3, 7, and S.) 41 is a rod attachedto a crank-arm iixed to the cock-plug. Said arm extends above thereservoir and outside the pedestal to any convenient point for itssuitable manipulation, and may be made to close the cock by gravity orin any convenient manner. The rate of the discharge, as described of thehydrostatic seat-supporting columns, can be regulated by adjusting thefemale screw 42 upon its counter part 43 to vary the width of thedischargiiig-passage 43.

rllhe purpose of the above-described device is to regulate the rate ofthe escape of a liquid such as oil independently of any regulation bythe cock.

The device is claimed in my application, Serial No. 623,231, iiledFebruary 13, 1397.

In Figs. 10 to 14 is illustrated an improved head-rest for a dentalchair. 44 denotes the ball of a universal joint, such as commonly usedto support head-rests. Said ball is made detachable and interchangeablefor convenience in applying the rest to different chairs using balls ofdifferent sizes. Said ball has a screw-thread connection with theS-shaped piece 45. The male part of this joint may be made slightlyfrusto-conical. It is slotted at 4G to receive a securing or tapered pin47. The purpose of the slot is to insure that the pin-hole 4S ofany-sized ball may be readily made to register therewith and thusfacilitate any desired change of balls. The pin is tapered to insure itsoperation in various balls. The upper end of the piece 45 is offrustoconical form and screw-threaded to receive a clam ping-n ut 49. Tothis nut is fixed a handwheel 49', preferably of wood, by which the nutis manipulated. Between this nut and the head 50 of the piece 45 areheld four arms having rings 51 integral therewith rotatably IOO IOS

IIO

IIS

supported on an unthreaded portion of the piece 45. Two of these arms(denoted by 52 and 53) are pivotally connected, each to the inner end ofa pad or pad-support 54. The ring 51 of the arm 53 is provided withteeth 55 or the like adapted to engage with similar teeth on head 50 tosecurely lock these parts together when they are properly engaged forthe purpose by suitably turning the nut 49.

IVhenever it is desired to adjust the arms about their support the nut49 should be unscrewed sufficiently to permit the several rings to havea small movement lengthwise of the supporting-post 45, whereby they are'loosened or unlocked to permit their rotation and the consequentoperation of their contiguous inclined surfaces. If it is desired toadjust the arm 53, the nut should be loosened sufficiently, so that theteeth at 55 may be disengaged. These teeth are made tine to facilitatethe turning of the ring pertaining to arm 53 when said nut is butslightly loosened.

The construction provides for several adjustments of each pad. Forexample, the arm 53 being held by the hand against rotation, the arm 57can be rotated about 45 to change the inclination of the pad by movingits upper part. The arm 57 being held in like manner, the arm 53 can berotated and the pad tilted by a suitable movement of its lower part, theupper part remaining nearly stationary. Thus, if it be desired to changethe inclination of the pad without materially changing the elevation ofits upper end, then an arm, as 53, for example, can be manipulated andthe arm 57 left undisturbed or held by the hand, if necessary; or if 57be held and 53 suitably manipulated the inclination of the pad can bechanged withoutmaterially changing the elevation of its lower end. If,in any case, the arms do not bind together sufliciently to maintaintheir position bythe operation of the inclined surfaces, then the partscan be tightened by the nut. The four arms may be simultaneously rotatedabout 45 to change the dist-ance between the pads. The two arms on oneside can be similarly moved without any movement of the other two. Allthe arms may be moved to one side to hold the head of a patientsidewise, and the pads can be variously inclined contemporaneously withsuch movement or with any other desired movement of all the arms.

The outer end of each pad has a pivotal connection with a connecting-rod56, which joins it to an arm 57 or 58 by a pivotal connection therewith.

` rlhe rings 51 of the arms 57 and 58 and of arms 52 and 53 have theirproximate faces formed each with two corresponding inclines 59 and GO,opposing similar inclines of its contiguo us ring, the constructionbeing such that each pad can be separately adjusted to any desired angleby its independent manipulation and such that both pads are immediatelyclamped and held in fixed relation by simultaneously pressing themapart, as by the action of the head pressed between them, the clampingbeing eii'ected by the close enga-gement of the opposite inclines of therings.

61 (see Figs. 14 and 11) denotes washers which are provided each with akey or projection 62, extending into a groove 63 to prevent the washerfrom being rotated, its object being to prevent the contiguous ringbeing rotated by the clamping-nut in one case or by the adjacent rin gin the other.

The washers being interposed between t-he rings and held by the keys arenot rotated by the friction of a ring or of rings, so that each of thelatter with its arm can be rotated without disturbing any other.

It is obvious that several of the improvements herein claimed areapplicable to other than dental chairs and that some of them .are notnecessarily limited to their principles of operation and mechanicalconstruction to chairs, and such parts are described and claimed inrelation to dental chairs for convenience only.

Having described my invention, what I claim is- 1. In a dental chair thecombination of the telescopin g tubes mediately connected to the seat,two pumps, and separate passages one from cach pump leading to adistinct tube whereby both pumps may be used to raise the chair,substantially as described.

2. In a dental chair the combination of the telescoping tubes mediatelyconnected to the seat, two pumps, and separate passages one from eachpump leading to a distinct tube ICO whereby both pumps may be used toraise the chair, the operating-levers, and theV spring connected'to thepiston-rod of one of the pumps and adapted to be compressed by theoperation of the levers and then to operate the pump to which it isconnected, by its eX- pansion, substantially as described.

3. The combination of pumps 18 and19, a plunger-tube 8 bearing on theseat-frame, the oilinlet tube 28 communicating with one of the pumps andwith the said plunger-tube, the extension-tube 15 having at its foot apiston-packing, and the fixed tube 14 the space within said latter tubebelow the pistonpacking of tube 15 communicating with a passage 27leading to the other pump, all substantially as set forth whereby tubes8 and 15 can be simultaneously and continuously raised by the pumps,substantially as described.

4. The combination in a dental chair of two pumps, mechanism tosimultaneously move the pump-pistons in opposite directions, a springconnected with one of the pump-pistons and adapted to be compressed bysaid mechanism to empty one pump and till the other, and an adjustabletension device to vary the initial t-ension of the said spring,substantially as described. l

5. In seat raising and lowering mechanism the combination of avertically-movable tube IIC with a fixed part and an interposed endlessseries of balls arranged in an endless channel a part of said ballsbearing upon the movable tube, said channel being formed in anadjustable receptacle, and devices for adjusting said receptacle to varythe friction on the balls.

6. In seat raising and lowering mechanism the combination of thepedestal, a tube fixed therein, a vertically-movable extension-tube andseveral series of balls bearing upon the extension-tube at distinctpoints in its circumference, and a device for varying directly thefriction of one-series of balls and indirectly varying that of the otherseries, substantially as described.

7. In seat raising and lowering mechanism the combination of thepedestal, a tube fixed therein, a vertically-movable extension-tube,several series of balls bearing upon the extension-tube at distinctpoints in its circumference, and a device for-varying directly thefriction of one series of balls and indirectly varying that of the otherseries, said device consisting of a rod or bar having an inclined face,and an adjustable ball-receptacle having a similar incline,substantially as described.

8. The combination of the pedestal 2, the vertically-movable tube 9provided with lengthwise grooves both on its interior and exterior, aplunger-tube, guide-wheels journaled one in the pedestal and one in theplunger-tube and running in said exterior and interior groovesrespectively, said wheels acting as antifriction devices for the severalparts and also preventing the rotation both of tube 9 and of theplunger-tube, substantially as described.

9. In a dental chair a head-rest comprising two pads adapted to beseparately manipulated to vary the inclination of either, and devicesfor clamping the pads in fixed relation to each other by simultaneouspressure on the face of the pads, as by suitably resting the headbetween them, substantially as described.

lO. Inadental chairahead-rest comprising two pads adapted to beseparately manipulated to vary the inclination of either, and devicesfor clamping the pads in fixed relation to each other by simultaneouspressure on the face of the pads, as by suitably resting the headbetween them, said devices consisting of inclined planes formed on thepadsupports and adapted to be forced together and thus locked by suchpressure.

11. In a head-rest the pad-supports com- Y prising the arms providedwith supporting- 45 fixed to said ring-support at its end opposite thehandle, substantially as described.

12. In a head-rest the pad-supports comprising the arms provided withsupportingrings having their contiguous faces formed with similar'opposing inclines and a support for the rings, and a washer or annulusprovided with a projection, said ring-support having a groove to receivethe projection and prevent the rotation of the washers, substantially asdescribed.

13. In a head-rest the pad-support having a slotted screw-threaded endin combination with a ball suitable for a ball-and-socket joint, saidball having a screw-threaded opening to receive the pad -support and atransverse opening to receive a 'securing-pin, and the pin,substantially as described.

14. In a head-rest the pad-support having a slotted screw-threaded endin combination with a ball suitable for a ball-and-socket joint, said.ball having a screw-threaded opening to receive the pad-support and atransverse. opening to receive a securing-pin, and the pin, said pinbeing tapered, substantially as described.

15. In combination a chair-pedestal, two pumps, a T-shaped lever pivotedto the pedestal the ends of the cross-piece of said lever beingpivotally connected by intermediate parts with the pumppiston, wherebythe pump can be worked by causing said lever to oscillate about itspivot, tubes containing a hydrostatic column, and a bent lever 2O havinga fulcrum 21 and loosely connected within the pedestal to the foot ofthe said T-shaped lever and extended to the outside of said pedestal,whereby the bent lever oscillates said T-lever, substantially asdescribed.

16. The combination in a dental chair of a plunger-tube 8 bearingagainst the seat-fram e, a liquid-holding tank or reservoir, a pumpsituated in said reservoir, a central tube 17 situated within theplunger-tube and having free communication above with said latter tubethroughout its entire length in every sitnation and communicating belowwith the pump, and a tube surrounding the plungertube, said latter tubeshaving at the foot of each a liquid-tight closure between it and saidcentral tube, whereby the latter guides both of the former and wherebyliquid can be forced through said central tube into the plunger to raisethe seat, and means for raising the tube that surrounds the plunger,substantially as described.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

MONT C. MERKER.

Witnesses:

BENJ. R. GATLIN, FRANK D. BLAcKrsToNn.

